Ignition-plug



o. ALLEN, JR'.

IGNITION PLUG.

APPLICATION FILED JAN-6. I919- Patented Aug. 26, 1919.

INVENTOR wlmsm;

y M M H A UNITED STATES PATENT OFFICE.

' OGLESTBY ALLEN, JR., OF CHICAGO, ILLINOIS.

IGNITION-PLUG.

Specification of Letters Patent.

Patented Aug. 26, 191 9 Application filed January 6, 1919. Serial No.269,766.

marked thereon, which form a part of this specification.

This invention relates toimprovements in spark or ignition plugs forexplosion ongines, and the invention consists in the combination andarrangement of the parts shown in the drawings and described in thespecification, and is pointed out in the appended claim.

Among the objects of the invention is to provide an ignition plug whichis made of few readily fabricated parts; which is exeeedingl y durableand rugged; the construetion of which is suchthat theplug elements unaybe readlly taken apart tor the purpose of oilicientl y cleaning the plugelements and the parts of which are so constructed and arranged as toreliably localize and limit the sparking zone at the ends of theterminals and avoid fouling of the terminals.

In the drawings,

Figure .l is a. side elevation with parts broken away oi an ignitionplug embodying my invention.

Fig.2 is a side elevation of a removable assembly of the plug whiclrcarries the terminals;

Figs. 3, 4, and 5 are details of a removable element which in partconstitutes the grounded terminal of the plug.

Reference herein is made to a grounded terminal to indicate what isherein shown as a tcrminal which is grounded on a metal part ployed forsake of simplicity of description i and is not intended to be limiting.

As shown in the drawings, 10 designates the cylinder head.

' as a whole the body of the plug which is a metal shell-like structure.It is formed with a reduced lower end 11 that is threaded to engage athreaded opening in the cylinder head and is provided at its upperend'with a polygonal portion 12 adapted to be engaged by 'awreuch tothread the shell into The bore of the shell 10 is formed with an upperenlarged portion 14 which is internally threaded and opens at the top ofthe shell, a smaller, axially aliued portion 15 which opens through thereduced lower end of the shell. The differential (lltU IIOtOIS oi thebore of the shell produce between the portions 14 and 15 an annular flatshoulder 16.

17 designates as a whole an insulating core the core is formed adownwardly facing annular shoulder 21 and between the intermediateportion 19 and the extended portion 20 is formed an upwardly facing!annular shoulder 22. 24 designates a tubular nut that is extcriorlythreaded tov engage the threads of the larger portion 14 of the shellbore and is formed with a polygonal flange 25 for engagement by awrench. The lower end of the nut engages. the upwardl y facing shoulder22 of the core 20 and when screwed down into the shell serves to forcethe shoulder 21 of the core downwardly toward the internal shoulder 16of the shell. The said core 17 ,is made of suitable insulating material.he core is made of such length that the lower or inner endthereof'extends well beyond the reduced lower end 11 of the shell. I

Said core is axially apertured to receive a close fitting rod 26, thelower or inner cud of winch extends below or inslde said reduced end ofthe core to constitute the live terminal 27 of the plug. The rod isthreaded at its upper end to receive the usual bind- 1 'ingniits, andmay formed on. a member of conducting that is removabl' tween the shouldand shell, respectively. As herein shown,

be non-rotatabl y fixedto the eolre in any suitable orpreterred manner.

,. The grounded terminal or terminals are i'naterial. confined in theshell bers 21 and 16 of the core there are two grounded terminals 28arranged one at each side of the live terminal 27, andthey are formedintegral with or electrically connected to a flat ring 29 which is of adiameter to snugly lit in ,the lower the live terminal is also favorablefor proper sparking between the terminals. The said arms 30 are alsoshown as convexly curved on their outer sides 'and lit/closely thesmaller circular portion 15 of the shell bore, belng (-ontined betweenthe mnerwall ol' the said reduced portion of the bore and the lowerreduced portioniltl ol the insulating core 17. This construction servesto'hold the arms, which are in themselves preferably of suitablerelative the ire terminal.

-'l o rcmove'the operative parts ol' the v we the nut 25lSdlTlSClIBVl/Qd from the shell,

- whereupon the core,

cal lying. the live term1- nal, may he'ieadily lifted away from thesh'ell.. 'lhereatter thermg 29 which carries the grounded terminals maybe lifted out of the shell. Said ternnnals,-when. thus removed from theshell, are Free to be cleaned as separate parts, and the bore ol' theshell may bealso readily cleaned hy 'uim'ing a cleaning parent.

brush or swab therelhrongh, as will be up \Vhen the parts are cleanedthe ring 25), carrying .the tcrn'iinals 28, is dropped into the shellupon the shoulder 16, after which the core is' inserted into the shellwith the lower reduced end between the units 30 and with. the downwardlyfacingshoull'ace of the ring. lhereal'ter the nut 25 is screwed downagainst the upwardly facing shoulder 22 oi the core which serves toforce therii'ig 29in close contact with the shoullt will lhusbe obirvedthat a very good electric contact is itlillllttilletl between thegrounded terminal faces of the ring and coetween the periphery of actingshoulder,

stiffness, rigidly in place device and. the shell, which Contact o curs7 at, the fiat meetm the ring and the unthreaded portion of the shelland between the arms 30 and the inner wall of the reduced portion 11 ofthe shell.

()no advantage of the construction described is due to the removabilityofthe 7 core' and all of-- the terminals freely upwardly from the shellso that when the plug is disassembled said terminals may be freelycleaned of carbon deposits. Another ad-- vantage "of the particularembodiment of the invention shown isdue to the fact that when r the coreand terminals are withdrawn-free access may be had to the shell bore toth0roughly .clean the same without liability of destroying the relativepositions of the terminals when the operative parts are again assembled,such aS is likely to occur in known forms of ignition pl'gs in which theground ed terminals are fixed toand carried by the shell. A furtheradvantage ofthe construetion disclosed is the means by which thegrounded terminal device is "clamped between the shell and theinsulating core and i "which permits ready removal (if-said core and thegroumled' terminal device and convement assembling of sald parts;Another advantage of the construction shown is due to the bracing of thearms which carry the 1 grounded terminals. in this connection it willbenoted that said arms aremade of substantial cross section. so thatthey are -1I1 themselves quite stitl' which, taken in con-m nection withthe eloseconfining of the arms along their length between the shell andcore insuresa deliniteor nonvarying spacing of the term nals. A furtheradvantage at the UUHStl'HOtIOl] IS found in the tact-that the terminals27 and 28 extend beyond both the core 30 and 'the metallic shelland are,delinitely spaced a distance apart at; their ends less than the distanceof protrusi'onof the core l'roni the shell. "Therefore the terminals aresnlriectedtothe direct action of the explosion in themngine cylinderand, being relatively narrow,.are in the influence of tlle'lOt'flliZtitlellects elf-sm rking so as to. be kept free-from carbon deposits in allparts thereof that project beyond the core and thereby limit or localizethe sparking area, at the ends of the sparking terminals.

I claim as my invention:

An ignition plug for explosive engines I I I comprising a metallic shellformed with an der 21 thereof resting against the upper upper enlargedand a lower reduced bore and with a shoulder betweenthem, a one-pieceextending axially through the core and beyond the inner end thereof, anda ring clamped between the shell and core shoultiers and provided withangularly spaced arms which are confined and braced between the eore andshell and in Contact with the shell and extending beyond the core, saidnrms beim. turned at their Fr b. nnrlR toward eneh other and the liveterminnl and spaced from the live terminal to constitute 10 the groundedterminals of the plug.

In testimony whereof I eluim the foregoing as my invention. I hereuntoappend my signature at Chicago, Illinois, this second day of January,1919.

()(lLESBY ALLEN, JR.

